Stock size estimation of the Mexican crab, Cancer johngarthi Carvacho, 1989 on the southwestern peninsula of Baja California, Mexico

Stock size of the Mexican crab, Cancer johngarthi was evaluated off the southwestern coast of the peninsula of Baja California (23 degrees 19' to 26 degrees 04'N 110 degrees 16' to 113 degrees 32'W) from three trap surveys executed from November 2002 to February 2003 on a commercial vessel. Surveys were made in depths of 80 to 300 m, using lines with an average of 87 traps per line, and a total of 183 hauls. Available stock size was estimated through a stock-reduction model considering both closed and open population assumptions. For all surveys, 15 experimental areas were selected. A total of 393,272 crabs were caught during the operations. The unit of effort was defined as hour-trap (h-t), and latitudinal gradient of catch rates (crabs per h-t) were observed. The average available stock-size ranged between 0.127 and 14.3 million crabs and catchability from 0.0000089 to 0.0013 crabs/h-t. The average harvest rates over the 15 experimental areas were about 1%. Even when results suggest a possible development of a new fishery, we suggest to realize more research specifically aimed at seasonal variation, reproductive aspects, and to execute an analysis of variation of catchability and stock size in order to predict conditions to initiate a commercial exploitation of the Mexican crab, Cancer johngarthi off the southwestern coast of the peninsula of Baja California.